Oldest full fossil yet for speedy mammal

A 160 million-year-old fossil suggests that flexible ankles and versatile ridged teeth were key to the success of a group of ancient mammals called multituberculates.

“Despite the success of the multituberculates, the earliest fossils are very fragmentary. Now, we finally have a complete skeletal fossil that allows us to paint a coherent picture of the evolutionary origin of these prolific and important ancient mammals,” says Zhe-Xi Luo, professor of organismal biology and anatomy at the University of Chicago.